Process for impregnating thick textile products with latex under great hydraulic pressures



PROCESS FOR IMPREGNATING THICK TEXTILE PRODUCTS WITH LATEX UNDER GREATHYDRAULIC PRESSURES Filed Sept. 17, 1932 p 25, 1934- J. DUARRY-SERRA1,974,879

Patented Sept. 25, 1934 PROCESS FOR IMI'BEGNATING THICK TEX- TILEPRODUCTS WITH LA'IEX UNDER GREAT HYDRAULIC PBESSURES Juan Dnarry-Serra,Barcelona, Spain Application September 17, 1932, Serial No. 833,613 InGermany January 13, 1932 9 Claims. (Cl. 9l.88)

This invention refers to a process for impregnating thick textileproducts with latex under great hydraulic pressures.

The invention has nothing to do with the im- 6 pregnation of threads andfabrics with rubber solutions on the basis of organic dissolving agentssuch as benzol, benzine, carbon tetrachloride etc., and it has nothingin common with the impregnation with latex of textile threads and fine lspun materials, which, during the following proces of manufacture serveas semi-manufactured goods for the elaboration of various kinds offabrics, driving belts, etc. f

The impregnation of fabrics in closed containld ers by means of a vacuumand subsequent pressure is known through the Austrian Patent No. 84,510,and the English Patent 316,335, but with these two systems it is notpossible to make the latex penetrate right inside the fabric, belt,rope, hi1 etc., especially when they are tight and thick, and under nocircumstances is this possible when a um pressure of to pounds to thesquare inch is used, as in the case of the English patent.

1:". her there is another process disclosed in the 5).) German PatentNo. 169,401, according to which, with very expensive machines, whichform a row of calender-s, the fabric is mecically stretched, opened andheated at the e time. process, "however, cannot be utilized for later,he

3i? cause, without a high hydraulic pressure the sub stance would onlyenter the big opegs and pores, but it would not go into the inside oithe single threads of the fabric, especially when these are closetogether. The 11ml; pro for this purpose would be atmospheres.

The invention consists in forcing the latex, preferably in aconcentrated form, into the ten tile products under very high pressuresrang between to and too atmospheres. en such or high hydraulic pressuresare used, nal later would give a completely negative ret, inns= much as,owing to the irlction which occurs as the substance penetrates thefabric, it would co= te at once, and make -further penetration aspossible. First oi all, therefore, the latex must be stabilized in orderto avoid the tion. The process oi stabilizing later to. avoid thecoagulation rting ,ironi not in well known, but the special 1': to avoidtion 5i due to friction during the impretion is new.

in view of the colloidal condition oi the latex,

in that as a consequence 1. an extremely rapid decom= position y set in,which, under certain circ= so may on snow erplmons; There:

fore it is absolutely necessary to prevent this,

otherwise it would not be possible to employ the and the difliculty.consists in the extraction of 68,

the water which Has entered the product. In the case of thin fabrics,threads, etc., this is easily achieved through coagulation andvapourizing, for instance by mechanically applied pressure. when thicktextile products have to be treated, however, this process cannot beused, for of course the upper surface coagulates first, when the usualmeans-acetic acid, alum, chloride of 'iron etc., are employed, and animpermeable coat of rubber is formed at once on account of which thewater is still more completely imprisoned in the interior. when thecoagulation takes place exclusively through the action of; heat, ratherthick rubber coatings are also formed; and on these being broken throughthe action of the stem 30 inside the tension set up is so great,and thetempera w high that both the rubber and the fabric are surged. Inaccordance with, the process described in the present specification,

:,m carbonate is mixed with the latex, which even at lowand harmlesstemperatures gives on a e amount of gas, and when the 1.11M. beencarried out properly the result is the production of pores inside thefabric. As the pre exerted by the gas inside rises, the go coating orrubber which closes these pores be torn apart, and the moisture then beable to escape in the form of water or steam through the ole thus openedup.

By means oi the above described process, there g5 tore, it is possiblethoroughly to impregnate the thickest textile products with later derthe highest we and also extract all the water from the inside, which wasnot possible up to the prwent. 31m

It well icnown that in the case oi textile products of medium,thicinuess it is possible to impregnate them satisfactorily Evith rubberby the use oi the o r. rubber solutions, but

in this care the highest point of concentration roe is to per centrubber and the remaining to per cent is the solvent. By the useofprocess, which precludes the utilization of high pre, for the usalready given only a mail p portion oi rubber can be put into the insidelit of the fabric. The latex, however, can be concentrated up to thepoint that it contains up to per cent of rubber, so that by employingthe above mentioned process, an amount of pure rubber can be made toenter the fabric, which is many times greater than the amount introducedby the hitherto known process, based on the use of the said solutions. l

The present position respecting the impregnation by means of latex incomparison with impregnation with rubber solutions has been made knownby the work of Dr. Hauser, from which it is understood that afterfifteen different impregnation processes, rubber has not been in--troduced into the interior of cord threads steeped in latex.

See Mitteilungen aus dem Arbeitsbereich der Metallgesellschaft A. G.,Frankfurt/Main, volume 5, November 1930.

The following is a detailed description of the process forming thesubject matter of the present application.

Treatment of the latex Some material must be mixed with the latex whichincreases its viscosity and also serves as a stabilizing agent, so thatwhen entering the fabricthe friction may be reduced to a minimum, andthus the coagulation may be prevented.

There are various substances appropriate for this, for example thevarious kinds of water soluble gums, such as Karaya, Gum arabic,tragacanth, and also the fluid exuded by different kinds of seeds such.as linseed etc. However, it has been found that besides this, moreespecially the sap of certain varieties of cactus plants, both increasesthe viscosity and also has an excellent stabilizing effect, so thatalcohol in small quantities canbe added to the latex with this sap,without any coagulation occurring. Among the very numerous kinds ofcactus plants those must be eliminated whose sap is acid and thereforecan be added. Ofall the oils that have been triedior the purpose, thebest-has proved to be castor oil, and also linseed oil can be added, forit facilitates the-drying after the impregnation. While this material isbeing gradually added to the latex, it is recommended that a littleainmonia water he added, so as to avoid the formation of a skin on theupper surface of the latex. Latex prepared in this way will notcoagulate even under high pressure and with great friction. A very goodformula is the following:-

To this mixture must then be added the other materials necessary for thevulcanizing, such as sulphur, oxide of zinc, accelerators andantioxidants.

After the latex is completely stabilized and has a high viscosity, stillother substances must be added to it, which facilitate the penetrationinto the threads of the fabric. Such materials are already known, andthey are chiefly used in the dyeing of textiles to make the dyes enterthe fabric better or to make the colours fast. For this purpose the bestsubstance has been found to be alcohol in a specially prepared form. Thealcohol coagulates the latex at once by imelf, and to overcome thecoagulating effect of the alcohol it must be added to the castor oilsoap in a 10% solution. The desired effect, i. e. the facilitating ofthe penetration of the latex, is, however, fully achieved by means ofthe alcohol. 5 per cent of this mixture of castor oil soap with alcoholcan be added to the'latex. This product should not be added to the latex(in the exact quantity required for impregnation) until the last moment,for, if the alcohol is allowed to remain for a lc-ng time incontact withthe latex, it could, even in this altered form, give rise tocoagulation. Further, 3 to 5 per cent ammonia carbonate is added, tosecure the formation of pores during the process of drying in connectionwith the impregnation procedure. to ensure the avoidance ofdecompo'sitionunder high pressures and as a corresponding precautionagainst explosions, about 5 per cent silicate of soda (waterglass) isadded. When this precaution is taken, as confirmed by tests, even if thepressure exceeds 800 atmospheres no explosion takes place. The followingmay serve as the complete formbla:-

Parts Latex with 60 per cent dry content. 80 Sap of the nopal cactusbelong ng to the order "Nopalea coccinellifera 15 Castor oil soluble inwater 5 Ammonia water 3 Alcohol in oil soap 5 Silicate of soda(waterglass) 6' Linseed nil 6 Ammonia carbonate 4 Colloidal sulphur 2Colloidal oxide of zinc 6 Piperidine penta methylene di-thiocarbamate0.5 25 Di-thio-carbamate cyclohenlethylaminmu 0.5 Diphenvlguanidin 0.5

The fabrics to be impregnated must be as free from acids as possible. Ifthey may contain acids, as for instance in the case'of Esparto grass, itis strongly recommended to wash the products before the impregnationtakes place, and to treat them with carbonate of soda.

The drawing shows an installation by means of which impregnation may becarried out in accordance with the foregoing indications:1 is animpregnating cylinder with strong walls, 2 is a latex container, 3 isthe vacuum pump, 4 is a three-way cock, 5 is a throttle valve, 6 and '7are control valves in the covers of the two containers, 8 is a hydraulicpressure pump, 9 a pressure container with a piston 10, on which thepressure water acts, and there is a piston 11, which exercises pressureon the latex. 12 is the water chamber and 13 is the room for the latexwhen it is under pressure. 14 is a hollow space produced on account ofthe difference between the crm sections of the two pistons 10 and 11.15, 16, 17 and 19 are four shutting-off cocks and 18 is an exhaust cock.

The installation works as follows:- At the beginning the container 2 isfilled with prepared latex, and the container 1 is empty.

The material to be impregnated is put into the container 1, the cover isput on and the cocks 5, 7 and 17 are closed, 19 being opened, and thenthe air is taken out of the container 1 by means of the vacuum pumpuntil the highest possible vacuum is produced. So soon as this has beendone, the cock 19 is closed, and communication between the containers 1and 2 is established by opening the cock 5. i The latex thereupon entersthe pressure chamber from below and fills it completely, after which thevalve 6 in the cover of the container 2 is opened and thustheatmospheric pressure can act on the contents of the container 2. Thecook 17 is then opened, and the piston 11 comes under the influence ofthe pressure water, which enters the intermediate chamber 14 through thevalve 15, travelling in a downward direction, and the chamber 13 isfilled with latex by suction. Then the valves 5 and 15 are closed, 16and 18 opened, and pressure is given under the piston 10, whereby thelatex enters the container 1 from the chamber 13, the valve 7 be- 1 ingopened, until latex comes out of 'Z, and this guarantees that there isno more air in container 1. Then valve '7 is closed, and now thepressure inside the container 1 can be increased as much as desired. Thepressure will be normally 200 atmospheres, but in the case of very thickand very dense fabrics, for example in the case of thick ship's ropes,the pressure must exceed 800 atmospheres. On the other hand, when veryopen or loosely woven textiles such as jute soles or Espartograss aretreated, the pressure need not exceed to atmospheres. No textileproduct, however, can be treated at lower pressures it is desired to getgood results. The temperature during the impregnation process should bepreferably between 50 and 60 degrees, because the viscosity of all thecomponents of the mixture is the" most satisfactory at thesetemconsiderable time, cannot be thoroughly impreg nated, and even at apressure of 800 atmospheres they must be subjected to the pressure forhalf an hour.

During the process of impregnation, the vacuum pump will pump free ofair that portion of the container 2 not filled with latex, and when theimpregnation has been efiected, the latex will be sucked from container1 into container 2 just as at the beginning.

In connection with the impregnation, the material taken from thecontainer 1 will be subjected to a different treatment according to itsnature, though this treatment will always be essentially the same. Firstby some mechanical means the upper surface be cleared of the stickylatex preparation adhering to it. According to whether it is a case ofparticles of the fabric, loose threads or ropes material the cleaningprocess may be eifected by special knives orprofiled rollers betweenwhich the material continually passes. The single soles must be passedbetween the rollers one by one, and the material flattened out. Then thematerial is heated in order to drive out the water produced as a resultof the presence of the ammonium carbonate, and this heating can becarried out according to the nature of the outside of the material. Theobject, however, is always to secure the production of gas consequent ona moderate degree of heating, whereupon all the inside moisture canescape with the gas. If continuous products such as belts or ropes haveto be heated, this is bestv elfected by passing them through anexteriorly heated tube of the appropriate length, so that when theobjects in question come out of the opposite end of the pipe the dryingprocess is finished. When small pieces such as soles, have to betreated, these will be carried through the heated tunnel by means of anappropriate transport appliance.

It is advisable to coagulate the surface of the material after thetaking off of the first thick coat and before it comes into contact withfurther apparatus, and this can best be done with alcohol, as comparedwith all other coagulating agents because the alcohol completelyvapourizes'and leaves no. traces, whereas the various known acids, whenthey are used to excess, may

- adversely affect the finished product due to the deposit they leave.

After the water has been driven out by means of the treatment withammonium carbonate, the

product is extremely porous. So long as water is present in the latex,the'latter retains all its stickiness, and through the vapourizing ofthe water through the opened pores, no temperature will be reached thatis appropriate for very quick vulcanization, so experience hasdemonstrated that immediately after complete expulsion of the water, thelatex has not yet vulcanized, and therefore a complete and definiteclosing of the pores is possible. The closing of the pores is effectedby passing the material through two rollers, though it must not passthrough too fast. Then the impregnated and dried out product isvulcanized by means of any of the commonly mown vulcanizing processes,with the application of the necessary heat.

From the formula above set forth the m. cal man will see that this maybe done at a tem-= perature of less than 100 degrees centigrade.

I claim:

1. Process for impregnating thick and dense textile products with latex,consisting in treating the textile products with latex in a closedcontainer under a pressure excee 50 atmospheree, whereby the latex isforced into the prod= ucts.

2. Process for impregnating thick and dense textile products with latex,comprising: adding to the latex the sap of certain kinds of cactusplants, especially that from the leaves of the plant belonging to thegenus of Nopalea coccinellifer whereby its viscosity is increased andcoagu lation is prevented; and treating the textile products with thelatex in a closed container un== der a pressure exceeding 50atmospheres.

3. Process for impregnating thick and dense textile products with latex,comprising; adding the sap of the NopaZea coccinellifera to the la= tex,whereby its viscosity is increased and coagulation is prevented; addingcastor oil soap to the latex; and treating the textile products with thelater: in a closed container under a pressure exceeding 5o atmospheres.

4. Process for impregnating thick and dense textile products with latex,comprising: adding the sap of the Nopalea coccinellijera to the latex,whereby its viscosity is increased and coagulation is prevented; addingalcohol to the latex, whereby the impregnation is rendered morecomplete; and treating the textile products with the latex in a closedcontainer under a pressure exceeding atmospheres.

5. Process for impregnating thick and dense textile products with latex,comprising: adding the sap of the "Nopalea coccinellijera to the latex,whereby its viscosity is increased and coagulation is prevented; addinga mixture of alcohol and castor oil soap to the latex, the alcohol beingdeprived of its power of coagulating the latex by the admixture withcastor oil soap; and treating the textile products with the latex in aclosed container under a pressure exceeding 50 atmospheres.

6. Process for impregnating thick and dense textile products with latex,consisting in treating the textile products with latex in a closedcontainer under a pressure exceeding 50' atmospheres at a temperature of50 C. to 0., whereby the latex is forced into the products.

7. Process for impregnating thick and dense textile products with latex,comprising: adding the sap of the "Nopalea coccinellifera to the latex,whereby its viscosity is increased and coagulation is prevented; addinga mixture of alcohol and castor oil soap to the latex, the alcohol beingdeprived of its power of coagulating the latex by the admixture withcastor oil soap; and treating the textile products with'the latex in aclosed container under a pressure exceeding 50 atmospheres at atemperature of 50 C. to 70 C.

8. Process for impregnating thick and dense textile products with latex,comprising: adding the sap of the Nopalec cocciaellifera to the latex,whereby its viscosity is increased and coagulation is prevented; addinga mixture 01 alcohol and castor oil soap to the latex, the alcohol beingdeprived of its power of coagulating the latex by the admixturewith;-'castor oil soap; adding silicate of soda (waterglass) to thelatex; and treating the textile products with the latex in a god closedcontainer under a pressure exceeding 50 atmospheres. -i

' 9. Process for impregnating thick and dense textile products withlatex, comprising: adding the sap of the "Nopalea coccinellifera to thelatex, whereby its viscosity is increased and coagulation is prevented;adding a mixture of alcohol and castor oil soap to the latex, thealcohol being

